Poor wifi connection to stick up cameras

Hi all. Seem to be having an issue like some others with poor wifi connection to the cameras. I have installed 2 stick up battery cameras at weekend. one to the back of the house and one to the front. The rear camera has RSSI -71 and is less than 2m from a tp link wifi extender. I have bought a powerline wifi extender today to try and help with the front camera. This is less than 1m from the wifi extender and still shows RSSI -77. This is very poor. I have looked through forums but can’t find a solution. Any tips or help ?? I have brought both cameras into house and put them next to router and reset them. I still only get RSSI-60 Surely this is not good Thanks Roseyp